U.S. patent number 10,816,113 [Application Number 15/865,810] was granted by the patent office on 2020-10-27 for thermoplastic composite pipe with multilayer intermediate lamina.
This patent grant is currently assigned to Evonik Operations GmbH. The grantee listed for this patent is Evonik Operations GmbH. Invention is credited to Jasmin Berger, Horst Beyer, Juergen Franosch, Rainer Goering, Hans Ries.
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United States Patent |
10,816,113 |
Berger , et al. |
October 27, 2020 |
Thermoplastic composite pipe with multilayer intermediate
lamina
Abstract
A process for producing a thermoplastic composite pipe is
provided. The thermoplastic composite pipe thus produced contains a
liner, two or more composite layers composed of tape laminas, and a
single- or multilayer intermediate lamina arranged between
different composite layers. Composite formation between identical
polymers in the process achieves improved adhesion. The
thermoplastic composite pipe is especially suitable for offshore
applications in oil or gas production.
Inventors: |
Berger; Jasmin (Dortmund,
DE), Ries; Hans (Marl, DE), Franosch;
Juergen (Marl, DE), Goering; Rainer (Borken,
DE), Beyer; Horst (Marl, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Evonik Operations GmbH |
Essen |
N/A |
DE |
|
|
Assignee: |
Evonik Operations GmbH (Essen,
DE)
|
Family
ID: |
1000005141772 |
Appl.
No.: |
15/865,810 |
Filed: |
January 9, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20180195647 A1 |
Jul 12, 2018 |
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Foreign Application Priority Data
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Jan 10, 2017 [EP] |
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17150840 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16L
11/08 (20130101); F16L 11/16 (20130101); B29C
65/02 (20130101); B32B 37/06 (20130101); B29D
23/001 (20130101); B29C 63/06 (20130101); B29C
70/32 (20130101); B32B 27/08 (20130101); F16L
9/128 (20130101); B32B 1/08 (20130101); B32B
27/18 (20130101); B29C 70/026 (20130101); B29L
2023/22 (20130101); B32B 2305/08 (20130101); B29K
2101/10 (20130101); B32B 2398/20 (20130101); B29K
2105/08 (20130101); B32B 2597/00 (20130101) |
Current International
Class: |
F16L
11/08 (20060101); B32B 1/08 (20060101); B29C
70/32 (20060101); B29C 70/02 (20060101); F16L
9/128 (20060101); B29D 23/00 (20060101); B29C
63/06 (20060101); B29C 65/02 (20060101); B32B
27/08 (20060101); B32B 27/18 (20060101); B32B
37/06 (20060101); F16L 11/16 (20060101) |
Field of
Search: |
;138/141 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 056 703 |
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Jul 1982 |
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EP |
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0 364 829 |
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Apr 1990 |
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EP |
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0 618 390 |
|
Oct 1994 |
|
EP |
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0 673 762 |
|
Sep 1995 |
|
EP |
|
0 685 674 |
|
Dec 1995 |
|
EP |
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WO 95/07428 |
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Mar 1995 |
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WO |
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WO 99/67561 |
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Dec 1999 |
|
WO |
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WO 01/61232 |
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Aug 2001 |
|
WO |
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WO 02/095281 |
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Nov 2002 |
|
WO |
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WO 2006/107196 |
|
Oct 2006 |
|
WO |
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WO 2012/118378 |
|
Sep 2012 |
|
WO |
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WO 2012/118379 |
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Sep 2012 |
|
WO |
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WO 2012/149129 |
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Nov 2012 |
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WO |
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WO 2013/188644 |
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Dec 2013 |
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WO |
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WO 2014/140025 |
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Sep 2014 |
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WO |
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Other References
US. Appl No. 09/138,665, filed Aug. 24, 1998, Goering, et al. cited
by applicant .
U.S. Appl. No. 13/640,586, filed Feb. 7, 2013, 2013/0032240, et al.
cited by applicant .
U.S. Appl. No. 13/639,765, filed Jan. 31, 2013, Kuhmann, et al.
cited by applicant .
U.S. Appl. No. 15/395,449, filed Aug. 10, 2017, Lobert, et al.
cited by applicant .
Extended European Search Report dated Jul. 24. 2017 in Patent
Application No. 17150840.1. cited by applicant .
J.L.C.G. De Kanter, et al. "Thermoplastic Composite Pipe: Analysis
and Testing of a Novel Pipe System for Oil & Gas", Proceedings
of the 17th ICCM, 2009, 10 pages. cited by applicant.
|
Primary Examiner: Schneider; Craig M
Assistant Examiner: Deal; David R
Attorney, Agent or Firm: Oblon, McClelland, Maier &
Neustadt, L.L.P.
Claims
The invention claimed is:
1. A process for producing a thermoplastic composite pipe, the
process comprising: (i) applying a first composite layer comprising
a first tape to a tubular liner via welding, and (ii) applying a
second composite layer, which is produced by applying a second tape
to an outer surface of a first film and melting the outer surface
of the first film and a contact surface of the second tape either
beforehand, simultaneously or thereafter, to the first composite
layer and melting an outer surface of the first composite layer and
a contact surface of the first film either beforehand,
simultaneously or thereafter, wherein the tubular liner has a wall
comprising a thermoplastic polymer A in a region of an outer
surface thereof, the first tape comprises reinforcing fibres in a
matrix comprising a thermoplastic polymer B, the second tape
comprises reinforcing fibres in a matrix comprising a thermoplastic
polymer C, the polymer A and the polymer B are the same or
different, the polymer B and the polymer C are different, and the
surface of the first film which is brought into contact with the
first composite layer consists of a moulding compound comprising at
least 30% by weight of the polymer B, and the opposite surface of
the first film consists of a moulding compound comprising at least
30% by weight of the polymer C.
2. The process according to claim 1, wherein the second composite
layer is produced by bonding the first film and the second tape
over an area such that the second tape and a side of the first film
that contains more of the polymer C are welded to one another.
3. The process according to claim 1, wherein the polymer A and the
polymer B are different; said applying (i) is performed by applying
the first composite layer, which is produced by applying the first
tape to an outer surface of a second film and melting the outer
surface of the second film and a contact surface of the first tape
either beforehand, simultaneously or thereafter, to the tubular
liner and melting an outer surface of the tubular liner and a
contact surface of the second film either beforehand,
simultaneously or thereafter; and the surface of the second film
which is brought into contact with the tubular liner consists of a
moulding compound comprising at least 30% by weight of the polymer
A, and the opposite surface of the second film consists of a
moulding compound comprising at least 30% by weight of the polymer
B.
4. The process according to claim 3, wherein the first film and the
second film consist of two, three or more layers cohesively bonded
to one another.
5. The process according to claim 3, wherein at least one of the
first film and the second film comprises unidirectional reinforcing
fibres.
6. The process according to claim 1, further comprising: (iii)
finally applying an outer cover lamina comprising a polymeric
material.
7. The process according to claim 1, wherein the polymer A is
selected from the group consisting of polyolefin, polyamide,
polyphthalamide, polyethylene naphthalate, polybutylene
naphthalate, fluoropolymer, polyphenylene sulphide, polyether
sulphone, polyphenyl sulphone, and polyarylene ether ketone.
8. The process according to claim 1, wherein the polymer B is
selected from the group consisting of polyolefin, polyamide,
polyphthalamide, polyethylene naphthalate, polybutylene
naphthalate, fluoropolymer, polyphenylene sulphide, polyether
sulphone, polyphenyl sulphone, and polyarylene ether ketone.
9. The process according to claim 1, wherein the polymer C is
selected from the group consisting of polyolefin, polyamide,
polyphthalamide, polyethylene naphthalate, polybutylene
naphthalate, fluoropolymer, polyphenylene sulphide, polyether
sulphone, polyphenyl sulphone, and polyarylene ether ketone.
10. The process according to claim 1, wherein the reinforcing
fibres in at least one of the first tape and the second tape are
unidirectionally arranged.
11. The process according to claim 1, wherein an amount of the
reinforcing fibres in the first tape or the second tape is 10% to
85% by volume.
12. The process according to claim 1, wherein the reinforcing
fibres in the first tape or the second tape are selected from the
group consisting of glass fibres, carbon fibres, aramid fibres,
boron fibres, ceramic fibres, basalt fibres, silicon carbide
fibres, polyamide fibres, polyester fibres, fibres of
liquid-crystalline polyester, polyacrylonitrile fibres, polyimide
fibres, polyetherimide fibres, polyphenylene sulphide fibres,
polyether ketone fibres, and polyether ether ketone fibres.
13. The process according to claim 1, further comprising (iv) after
said applying (i) and before said applying (ii), cohesively bonding
further tape laminas that are of the same kind as the first
tape.
14. The process according to claim 1, further comprising (v) after
said applying (ii), cohesively bonding further tape laminas that
are of the same as the second tape.
15. The process according to claim 1, wherein the first film is a
single-layer film.
16. The process according to claim 1, wherein the first film is a
multi-layer film.
Description
The invention provides a flexible fibre-reinforced composite pipe
comprising an inner liner (also called "liner" for short
hereinafter), two or more composite layers composed of tape
laminas, and a single- or multilayer intermediate lamina which is
arranged between different composite layers and bonds them, and a
process for production thereof. The material for the inner liner,
the matrix for the tape laminas and the polymers for the
intermediate lamina are thermoplastic. The composite pipe according
to the invention is used for oil and gas production, especially for
the offshore production of oil or gas, as a riser, as an umbilical,
for the transport of the produced oil or gas across the seabed from
the well to the riser, or for transport on land.
In the prior art, what are called unbonded flexible pipes are very
frequently used for this application sector. Pipes of this kind
comprise an inner lining, typically in the form of a plastic pipe,
as a barrier to the exit of the fluid being conveyed, and also one
or more armour layers on the outside of this inner lining. The
unbonded flexible pipe may comprise additional layers, for example
one or more armour layers on the inside of the inner lining, in
order to prevent the collapse of the inner lining under high
external pressure. Such an inner armour is typically referred to as
carcass. In addition, an outer shell may be present in order to
provide a barrier against the ingress of liquid from the outside
environment into the armour layers or polymeric or metallic
functional layers further to the inside, and as protection against
outside mechanical stresses.
Typical unbonded flexible pipes are described by way of example in
WO 01/61232, U.S. Pat. Nos. 6,123,114 and 6,085,799; they are
moreover described in more detail in API Recommended Practice 17B,
"Recommended Practice for Flexible Pipe", 3rd edition, March 2002,
and also in API Specification 17J, "Specification for Unbonded
Flexible Pipe", 2nd Edition, November 1999.
The term "unbonded" in this context means that at least two of the
layers, inclusive of reinforcing layers and plastics layers, do not
have any mutual adhesive bonding. In practice, the pipe comprises
at least three armour layers which, over the entire length of the
pipe, have no mutual bonding either directly or indirectly, i.e. by
way of other layers. This renders the pipe flexible to an extent
that allows it to be rolled up for transport purposes.
In conventional unbonded flexible pipes, the armour layer(s)
usually consist(s) of steel wires, steel profiles or steel strips
arranged in the form of a spiral, where the individual layers may
be formed with different winding angles relative to the pipe axis
(tensile armour), and pressure armour wound primarily in the
circumferential direction. In such unbonded flexible pipes, the
steel component is exposed to the corrosive effects of the medium
being conveyed. Owing to the resulting choice of material and the
complex construction, pipes of this kind are comparatively costly.
The high intrinsic weight is very disadvantageous especially in the
case of relatively long risers for offshore oil production in deep
seas.
For some time, there have been descriptions of developments where
thermoplastic composite pipes are employed. These are pipes having,
as inner lamina, a single- or multilayer inner liner composed of
thermoplastic material. A composite lamina is applied thereto, in a
cohesively bonded or in some cases even unbonded manner, for
example by winding of unidirectionally fibre-reinforced tapes.
Composite pipes of this kind are disclosed, for example, in WO
95/07428 and WO 99/67561. The production thereof is additionally
described in WO 02/095281, WO 2006/107196, WO 2012/118378, WO
2012/118379 and WO 2013/188644.
It is a general problem in the case of these composite pipes that
the bonding between a fibre-rich tape lamina and the adjoining
surface in the case of a suboptimal material combination is
inadequate to withstand the stresses in installation and operation,
especially in offshore applications, such as attachments to
fittings or mounting with gripping devices, and the hard test
conditions to which constructions of this kind are subjected.
Mention is made here by way of example of the detachment of layers
in the rapid gas decompression test or under the action of
significant bending forces. Attempts are therefore being made in
the prior art preferably to use polymer of the same kind for the
tape matrix and an adjoining surface, for example the outer surface
of the inner liner (see, for instance, "Thermoplastic Composite
Pipe: An Analysis And Testing Of A Novel Pipe System For Oil &
Gas"; presentation by J. L. C. G. de Kanter and J. Leijten at the
ICCM 17 conference in Edinburgh, U K, 2009).
In the case of thermoplastic composite pipes with single-wall
liners, liner pipes made of polyethylene are used in the
low-temperature range (sustained temperature up to about 50.degree.
C.), and liner pipes made of polyamide such as PA11 or PA12 at
higher temperatures up to about 80.degree. C. At even higher
temperatures, high-cost materials such as polyvinylidene difluoride
(PVDF) or even polyether ether ketone (PEEK) are used. Taking
account of the demands on chemical stability, ageing resistance and
thermal stability, it is possible in many cases to use composite
comprising a matrix composed of PA11 or PA12. It is frequently
found to be appropriate to form the composite lamina from different
composite layers, where the different composite layers each have a
matrix based on different polymers. Thus, in many cases, the matrix
of the composite layer arranged on the outside may be based on a
polymer which is cheaper or has elevated flexibility. This is
possible since the outer region of the pipe wall is subject to
lower demands with regard to thermal stability, stability toward
the medium to be conveyed, and diffusion barrier action. However, a
question that generally arises in the case of combination of unlike
materials is how the necessary adhesion is to be achieved between
different composite layers.
The person skilled in the art is aware that the composite can be
formed from two different thermoplastic layers with one another
either via material compatibility or via chemical reactions.
Material compatibility exists in the ideal case when the same
polymer is involved. It is known from experience with multilayer
pipe development and multicomponent injection moulding that
chemical bonds can be achieved quite efficiently with elevated
temperature and residence time when melt is applied to melt, for
example in coextrusion. However, good adhesion of the identical
material combination is much more difficult to achieve when a
solidified surface first has to be surface-melted by a hot melt and
only little time is available for a chemical reaction. Even in the
case of polymers of the same kind, a bond thus established can have
inadequate strength. A better composite arises when the two
composite partners are melted at the surface thereof prior to
joining and then pressed against one another. However, here too,
the time for a chemical reaction is short, and so the bonds between
equivalent polymers generally have better adhesion than bonds that
have to be implemented through a chemical reaction or via material
compatibility (i.e. through diffusion processes).
The problem addressed by the invention is that of providing a
process for producing a thermoplastic composite pipe with which,
firstly, high degrees of freedom are achieved in the material
combination of liner, tape matrix of the first composite layer and
tape matrix of the subsequent composite layer, and which secondly
gives very good adhesion at the critical layer boundaries.
The underlying problem is solved in that tape laminas based on
different polymers are bonded to one another so as to produce a
film, one surface of which comprises the polymer B of the first
composite layer and the other surface of which comprises the
polymer C of the subsequent composite layer. The film is then
bonded to the first composite layer with application of heat and,
in a further step, bonded to the first tape lamina of the
subsequent composite layer with application of heat.
FIG. 1 provides a representation of one embodiment of the
thermoplastic composite pipe of the present invention.
The invention thus provides a process for producing a thermoplastic
composite pipe, comprising the following steps: a) providing a
tubular liner having a wall comprising a thermoplastic polymer A in
the region of the outer surface; b) providing a tape comprising
reinforcing fibres in a matrix comprising a thermoplastic polymer
B; c) providing a tape comprising reinforcing fibres in a matrix
comprising a thermoplastic polymer C; where polymer A and polymer B
are the same or different and polymer B and polymer C are
different, d) applying a tape provided in step b) to the tubular
liner by means of welding, e) optionally cohesively bonding further
tape laminas of the same kind to the tape lamina applied in step
d), f) applying a film or a composite which is produced in step g)
and is composed of a film and a tape provided in step c) to the
first composite layer thus formed, with melting of the outer
surface of the first composite layer and of the contact surface of
the film either beforehand, simultaneously or thereafter, where the
region of the contact surface of the film consists of a moulding
compound comprising polymer B to an extent of at least 30% by
weight, preferably to an extent of at least 40% by weight, more
preferably to an extent of at least 50% by weight, especially
preferably to an extent of at least 60% by weight and most
preferably to an extent of at least 70% by weight, and where the
region of the opposite (outer) surface of the film consists of a
moulding compound comprising polymer C to an extent of at least 30%
by weight, preferably to an extent of at least 40% by weight, more
preferably to an extent of at least 50% by weight, especially
preferably to an extent of at least 60% by weight and most
preferably to an extent of at least 70% by weight; g) applying the
tape provided in step c) to the outer surface of the film, with
melting of the outer surface of the film applied and of the contact
surface of the tape either beforehand, simultaneously or
thereafter; h) optionally cohesively bonding further tape laminas
of the same kind to the tape lamina applied in step g), where the
second composite layer is produced in steps g) and optionally h),
i) optionally finally applying an outer cover lamina composed of a
polymeric material.
In a first embodiment, polymer A and polymer B are the same. In
this case, in step d), the tape is applied directly to the outer
surface of the liner, with melting of the outer surface of the
liner and of the contact surface of the tape either beforehand,
simultaneously or thereafter.
In a second embodiment, polymer A and polymer B are different. In
this case, tape and liner are bonded to one another so as to
produce a film, one surface of which comprises the polymer A of the
liner surface and the other surface of which comprises the polymer
B of the tape matrix. The film is then bonded to the liner with
application of heat and, in a further step, bonded to the first
tape lamina with application of heat. Thus, the same concept as in
the bonding of different composite layers is used. Step d) here
thus consists of the following components steps: d1) applying a
film or a composite which is produced in step d2) and is composed
of a film and a tape provided in step b) to the tubular liner, with
melting of the outer surface of the liner and of the contact
surface of the film either beforehand, simultaneously or
thereafter, where the region of the contact surface of the film
consists of a moulding compound comprising polymer A to an extent
of at least 30% by weight, preferably to an extent of at least 40%
by weight, more preferably to an extent of at least 50% by weight,
especially preferably to an extent of at least 60% by weight and
most preferably to an extent of at least 70% by weight, and where
the region of the opposite (outer) surface of the film consists of
a moulding compound comprising polymer B to an extent of at least
30% by weight, preferably to an extent of at least 40% by weight,
more preferably to an extent of at least 50% by weight, especially
preferably to an extent of at least 60% by weight and most
preferably to an extent of at least 70% by weight; d2) applying the
tape provided in step b) to the outer surface of the film, with
melting of the outer surface of the film applied and of the contact
surface of the tape either beforehand, simultaneously or
thereafter.
The invention is to be elucidated in detail hereinafter, where
these elucidations, unless stated otherwise, explicitly relate
equally to the first and second embodiments.
The tubular liner generally has an internal diameter in the range
from 15 to 400 mm, preferably in the range from 20 to 300 mm and
more preferably in the range from 25 to 255 mm. Its wall thickness
is generally in the range from 2 to 40 mm, preferably in the range
from 2.5 to 30 mm and more preferably in the range from 3 to 20 mm.
The liner may have a single layer or multiple layers. If it has a
single layer, it consists of a moulding compound comprising at
least 30% by weight, preferably at least 40% by weight, more
preferably at least 50% by weight, even more preferably at least
60% by weight and especially preferably at least 70% by weight, at
least 80% by weight or at least 85% by weight of the polymer A,
based in each case on the overall moulding compound. If the liner
has multiple layers, the outer layer consists of this moulding
compound; the inner layer may consist of a moulding compound
having, for example, a barrier effect or a chemical protection
function with respect to components of the medium to be conveyed.
Inner and outer layers may be bonded to one another by an adhesion
promoter layer.
The polymer A may, for example, be a polyolefin, a polyamide, a
polyphthalamide (PPA), a polyethylene naphthalate, a polybutylene
naphthalate, a fluoropolymer, a polyphenylene sulphide (PPS), a
polyether sulphone, a polyphenyl sulphone (PPSU) or a polyarylene
ether ketone such as PEEK or PEK. In a preferred embodiment, the
moulding compound of the single-layer liner or the moulding
compound of the outer layer of a multilayer liner does not comprise
any further polymer aside from the polymer A.
The tapes provided in steps b) and c) comprise reinforcing fibres.
These may, for example, be glass fibres, carbon fibres, aramid
fibres, boron fibres, ceramic fibres (for example composed of
Al.sub.2O.sub.3 or SiO.sub.2), basalt fibres, silicon carbide
fibres, polyamide fibres, polyester fibres, fibres of
liquid-crystalline polyester, polyacrylonitrile fibres, and fibres
of polyimide, polyether imide, polyphenylene sulphide, polyether
ketone or polyether ether ketone. Preference is given here to glass
fibres, carbon fibres, aramid fibres and basalt fibres. The cross
section of the fibres may for example be circular, rectangular,
oval, elliptical, or cocoon-shaped. With fibres of cross section
deviating from the circular shape (for example flat glass fibres)
it is possible to achieve a higher fill level of fibre in the
finished part, and thus higher strength. The fibres may be used in
the form of short fibres or long fibres, or preferably in the form
of endless fibres, for instance in the form of a weave or more
preferably in the form of a unidirectional fibre lamina.
The proportion by volume of the reinforcing fibres in the tape is
generally 10% to 85%, preferably 15% to 80%, more preferably 20% to
75% and especially preferably 25% to 70%.
In the tapes provided in steps b) and c), the type of reinforcing
fibres and the proportion by volume thereof may be different.
The matrix of each of these tapes consists of a moulding compound
comprising at least 30% by weight, preferably at least 40% by
weight, more preferably at least 50% by weight, even more
preferably at least 60% by weight and especially preferably at
least 70% by weight, at least 80% by weight or at least 85% by
weight of the polymer B or of the polymer C, based in each case on
the overall moulding compound. The polymer B or the polymer C may,
for example, be a polyolefin, a polyamide, a polyphthalamide (PPA),
a polyethylene naphthalate, a polybutylene naphthalate, a
fluoropolymer, a polyphenylene sulphide (PPS), a polyether
sulphone, a polyphenyl sulphone (PPSU) or a polyarylene ether
ketone such as PEEK or PEK. Polymer B and polymer C are different.
This means that they are different in terms of chemical
composition; differences in molecular weight, in the degree of
branching or in the end groups are immaterial. The same applies in
the second embodiment to the differing nature of polymer A and
polymer B.
The tapes can be produced by any prior art method. The production
of unidirectional endless fibre-reinforced tapes is described in
detail, for example, in EP 0 056 703 A1, EP 0 364 829 A2, U.S. Pat.
No. 4,883,625, WO 2012/149129, WO 2013/188644 and WO 2014/140025.
Possible production methods are, for example, melt application,
impregnation with a polymer solution and removal of the solvent,
film impregnation or powder impregnation.
Typically, the tape used has a width of 5 to 500 mm and preferably
a width of 8 to 200 mm, while the thickness is typically in the
range from 0.1 to 1 mm, preferably in the range from 0.1 to 0.5 mm
and more preferably in the range from 0.15 to 0.35 mm. The overall
composite lamina, i.e. the sum total of all the tape laminas or
composite layers, here is in the range from 1 to 100 mm, preferably
in the range from 5 to 90 mm and more preferably in the range from
10 to 80 mm. For different tape laminas, it is possible to use
different tape geometries. The tapes used may have any suitable
cross section. Furthermore, it is possible to use different
reinforcing fibres for different tape laminas.
The polymers mentioned by way of example for polymer A, polymer B
and polymer C are well known to those skilled in the art and are
commercially available in a multitude of commercial grades, and
therefore there is no need for any more specific description.
Examples of useful polyolefins include polypropylene, polyethylene
and crosslinked polyethylene. Suitable polyamides are, for example,
PA6, PA66, PA610, PA88, PA8, PA612, PA810, PA108, PA9, PA613,
PA614, PA812, PA128, PA1010, PA10, PA814, PA148, PA1012, PA11,
PA1014, PA1212 and PA12, or a polyether amide or polyether ester
amide based on one of these polyamides. The polyphthalamide may,
for example, be PA66/6T, PA6/6T, PA6T/MPMDT (MPMD stands for
2-methylpentamethylenediamine), PA9T, PA10T, PA11T, PA12T, PA14T,
PA6T/61, PA6T/10T, PA6T/12, PA10T/11, PA10T/12 or PA612/6T.
Suitable fluoropolymers are, for example, polyvinylidene fluoride
(PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), an ETFE
modified with the aid of a tertiary component, for example propene,
hexafluoropropene, vinyl fluoride or vinylidene fluoride (for
example EFEP), ethylene-chlorotrifluoroethylene copolymer (E-CTFE),
polychlorotrifluoroethylene (PCTFE),
chlorotrifluoroethylene-perfluoroalkyl vinyl
ether-tetrafluoroethylene copolymer (CPT),
tetrafluoroethylene-hexafluoropropene-vinylidene fluoride copolymer
(THV), tetrafluoroethylene-hexafluoropropene copolymer (FEP) or
tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA).
Also useful here are copolymers based on vinylidene fluoride that
include up to 40% by weight of other monomers, for example
trifluoroethylene, chlorotrifluoroethylene, ethylene, propene and
hexafluoropropene.
The moulding compounds used in accordance with the invention may,
as well as polymer A or polymer B or polymer C, optionally comprise
further polymers and customary auxiliaries or additives. In a
preferred embodiment, the moulding compound for the liner does not
comprise any further polymers aside from polymer A. In a further
preferred embodiment, the moulding compounds both of the liner and
of the tapes for the first composite layer do not comprise any
further polymers aside from polymer A or polymer B.
The film applied in step f) is a single-layer film in a first
embodiment, and a multilayer film in a second embodiment.
In the first embodiment, the thermoplastic component of the film
consists of a moulding compound comprising at least 30% by weight,
preferably at least 35% by weight and more preferably at least 40%
by weight of polymer B, and at least 30% by weight, preferably at
least 35% by weight and more preferably at least 40% by weight of
polymer C, based in each case on the overall moulding compound.
Since polymers B and C are different, they are generally
incompatible with one another. In this case, either the moulding
compound has to comprise a compatibilizer, or the two polymers B
and C are at least partly joined to one another via chemical
reactions.
One example of a moulding compound with compatibilizer is a
moulding compound comprising a polyamide such as PA11 or PA12 to an
extent of at least 30% by weight, a fluoropolymer such as PVDF to
an extent of at least 30% by weight, and an effective amount of an
acrylate copolymer. Suitable acrylate copolymers are disclosed, for
example, in EP 0 673 762 A2. It is possible, for example, for 0.1%
to 10% by weight of the acrylate copolymer to be present in the
moulding compound; in the production of the moulding compound, it
is appropriate to premix the fluoropolymer and the acrylate
copolymer in the melt.
One example of a moulding compound with chemical linkage is a
moulding compound comprising a polyamide such as PA11 or PA12 to an
extent of at least 30% by weight and a semiaromatic polyamide or
polyphthalamide (PPA) such as PA6T/6, PA6T/66, PA6T/61, PA6T/10T or
PA6T/12 to an extent of at least 30% by weight. In the case of
mixing in the melt, because of the high temperatures,
transamidation reactions occur here, giving rise to block
copolymers having PA11 or PA12 blocks and PPA blocks. These act as
compatibilizers between the two components.
In the second embodiment, the multilayer film in the simplest case
consists of two layers. It preferably consists of three layers. It
may alternatively consist of four, five or even more layers. There
is only an upper limit to the number of layers in that it is
impracticable to extrude layers of unlimited thinness. For reasons
of practicability, the upper limit is therefore 9 layers and
preferably 7 layers.
Examples of two-layer films are: Layer oriented toward the first
composite layer and composed of a moulding compound comprising 50%
to 80% by weight of polymer B and 20% to 50% by weight of polymer
C, and layer oriented toward the second composite layer and
composed of a moulding composition comprising 50% to 80% by weight
of polymer C and 20% to 50% by weight of polymer B. The two
moulding compounds appropriately also comprise 0.1% to 10% by
weight of a compatibilizer. The percentages here, as in the
examples which follow, are based on the overall moulding compound
for the respective layer. In the case of a first composite layer
having an outer PVDF surface, the layer of the film oriented toward
the first composite layer consists of a moulding compound
comprising at least 30% by weight of PVDF and 2.5% to 50% by weight
of the acrylate copolymer disclosed in EP 0 673 762 A2; the layer
oriented toward the second composite layer consists of the same
polyamide as the matrix of the second composite layer, for example
PA11 or PA12, to an extent of at least 50% by weight. In the case
of a first composite layer having an outer PPA surface, the layer
of the film oriented toward the first composite layer consists of a
moulding compound comprising at least 40% by weight of the same
PPA; the layer oriented toward the second composite layer consists
of the same polyamide as the matrix of the second composite layer,
for example PA11 or PA12, to an extent of at least 50% by weight.
Both moulding compounds may additionally comprise 0.1% to 25% by
weight of a polyolefinic impact modifier containing acid anhydride
groups. In the case of a first composite layer having an outer PPS
surface, the layer of the film oriented toward the first composite
layer consists of a moulding compound comprising at least 50% by
weight of PPS and 3% to 30% by weight of a polyolefinic impact
modifier containing acid anhydride groups that may also contain
acrylate units (trade name, for example, LOTADER.RTM.); the layer
oriented toward the second composite layer consists of the same
polyamide as the matrix of the second composite layer, for example
PA11 or PA12, to an extent of at least 50% by weight. In the case
of a first composite layer having an outer PA11 or PA12 surface,
the layer of the film oriented toward the first composite layer
consists of a moulding compound comprising the same polyamide to an
extent of at least 40% by weight and 30% to 60% by weight of a
polypropylene or polyethylene containing acid anhydride groups; the
layer oriented toward the second composite layer consists of the
same polypropylene or polyethylene as the matrix of the second
composite layer to an extent of at least 50% by weight. In the case
of a first composite layer having an outer PEEK surface, the layer
of the film oriented toward the first composite layer consists of a
moulding compound comprising PEEK to an extent of at least 30% by
weight and a polyimide or polyether imide to an extent of 20% to
70% by weight; the layer oriented toward the second composite layer
consists of the same PPA as the matrix of the second composite
layer to an extent of at least 50% by weight, where the PPA for
this layer preferably has an excess of amino end groups to improve
adhesion. The PPA for the second composite layer may differ
therefrom in terms of the end group content.
Examples of three-layer films are: Layer oriented toward the first
composite layer and composed of a moulding compound comprising at
least 40% by weight of polymer B. This is followed by an adhesion
promoter layer composed of a moulding compound comprising at least
30% by weight of polymer B, at least 30% by weight of polymer C,
and optionally 0.1% to 20% by weight of compatibilizer. The layer
oriented toward the second composite layer comprises polymer C to
an extent of at least 40% by weight. In the case of a first
composite layer having an outer PVDF surface, the layer of the film
oriented toward the first composite layer consists of a moulding
compound comprising at least 30% by weight and preferably at least
50% by weight of PVDF. This is followed by an adhesion promoter
layer composed of an acrylate polymer according to EP 0 673 762 A2
or of a polyamide/acrylate copolymer mixture according to EP 0 618
390 A1. The layer oriented toward the second composite layer
consists of the same polyamide as the matrix of the second
composite layer to an extent of at least 50% by weight; just like
the polyamide for the adhesion promoter layer; examples of these
are PA11 or PA12. In the case of a first composite layer having an
outer PPA surface, the layer of the film oriented toward the first
composite layer consists of a moulding compound comprising at least
40% by weight of the same PPA. This is followed by an adhesion
promoter layer composed of a moulding compound comprising at least
30% by weight of this PPA and at least 30% by weight of the
polyamide to be bonded thereto. The layer oriented toward the
second composite layer consists of the same polyamide as the matrix
of the second composite layer, for example PA11 or PA12, to an
extent of at least 50% by weight. In the case of a first composite
layer having an outer PPS surface, the layer of the film oriented
toward the first composite layer consists of a moulding compound
comprising PPS to an extent of at least 50% by weight. This is
followed by an adhesion promoter layer composed of a moulding
compound comprising at least 50% by weight of PPS and 3% to 30% by
weight of a polyolefinic impact modifier which contains acid
anhydride groups and may also contain acrylate units (trade name,
for example, LOTADER.RTM.). The layer oriented toward the second
composite layer consists of the same polyamide as the matrix of the
second composite layer to an extent of at least 50% by weight, for
example PA11 or PA12. In the case of a first composite layer having
an outer PA11 or PA12 surface, the layer of the film oriented
toward the first composite layer consists of a moulding compound
comprising the same polyamide to an extent of at least 40% by
weight. This is followed by an adhesion promoter layer composed of
an acid anhydride-functionalized polyethylene (if the matrix of the
second composite layer is based on polyethylene) or an acid
anhydride-functionalized polypropylene (if the matrix of the second
composite layer is based on polypropylene). The layer oriented
toward the second composite layer consists of the same polyethylene
or polypropylene as the matrix of the second composite layer to an
extent of at least 50% by weight. In the case of a first composite
layer having an outer PEEK surface, the layer of the film oriented
toward the first composite layer consists of a moulding compound
comprising PEEK to an extent of at least 40% by weight. This is
followed by an adhesion promoter layer composed of a moulding
compound comprising at least 50% by weight of a polyimide or
polyether imide. The layer oriented toward the second composite
layer consists of the same PPA as the matrix of the second
composite layer to an extent of at least 50% by weight, where the
PPA for this layer preferably contains an excess of amino end
groups to improve adhesion. The PPA of the matrix of the second
composite layer may differ therefrom in terms of the end group
content.
The percentages by weight in these examples are merely
illustrative; they can be varied according to the general figures
given in the claims and the description.
In the second embodiment, the liner and the first tape lamina of
the first composite layer in step d) are likewise bonded by an
appropriate intermediate film. The same details are applicable here
as above for the film applied in step f); it is merely necessary to
replace the term "first composite layer" with "liner", "polymer B"
with "polymer A", "polymer C" with "polymer B", and "second
composite layer" with "first composite layer".
Single-layer films, in both embodiments, are produced in a known
manner by extrusion, and multilayer films in a likewise known
manner by coextrusion, extrusion coating or lamination.
The film to be applied is generally in the form of a tape. The film
tape is wound around the first composite layer or the liner in the
form of a spiral, the angle being dependent on the tape width and
the pipe diameter. All that matters is to cover the outer surface
of the first composite layer or of the liner substantially
seamlessly and preferably virtually completely seamlessly; the
winding angle is unimportant in principle, provided that
crease-free winding of this film lamina is possible.
Advantageously, the film is wound such that there is neither
overlapping nor gaps. However, slight overlaps or gaps may possibly
be tolerated. The winding is effected under a contact pressure
which is generated by the winding tension or by a pressing
apparatus. In order to increase the tensile strength of the film
and hence prevent tearing of the softened film in the course of
winding, one or more film layer(s) may contain unidirectional
reinforcing fibres. In order not to worsen the adhesion to the
adjoining layers, however, it is advisable here not to choose too
high a fibre content. In general, fibre contents in the range from
3% to 20% by volume are sufficient. A specific embodiment of this
is a film composed of three or more layers where the middle layer
(in the case of a three-layer film) or at least one of the middle
layers (in the case of a film composed of more than three layers)
comprises unidirectional reinforcing fibres. In this case, the
fibre content may, for example, be in the range from 3% to 40% by
volume. The unidirectional reinforcing fibres are generally
oriented in axial direction of the film tape. Multilayer films of
this kind that comprise a fibre-reinforced layer can be produced,
for example, by laminating the individual layers, by extruding
unreinforced layers onto a reinforced layer, or by extruding
moulding compounds onto a spread fibre lamina.
In one possible embodiment, the film provided is bonded directly to
the tape of the first tape lamina of the subsequent composite layer
over an area; in this case, the tape and the side of the film that
is rich in the corresponding polymer are welded to one another. In
this embodiment, step d2) or step g) is undertaken. One advantage
of this embodiment is that the winding tension required cannot lead
to breakage of the film, since it is reinforced by the tape. A
composite of this kind can be produced, for example, by laminating
tape and film.
What is important is that both contact faces are melted in the
welding of first composite layer and film or of liner and film. In
one embodiment, the two contact faces are melted at the surface,
for example by means of infrared radiation, hot air, hot gas, laser
radiation, microwave radiation, or directly by contact heating. The
contact faces that have been melted at the surface are then pressed
against one another, for example with the aid of the winding
tension or by means of a contact body, for instance a roller or a
jaw. The contact pressure should then be maintained until the
molten regions have solidified. In a further embodiment, the film
is wound up and then melted from the outside, either indirectly or
else directly by means of a heatable contact body. The heating
output has to be calibrated such that the outer surface of the
first composite layer or of the liner also starts to melt here.
Thereafter, the contact pressure is maintained until the regions
melted at the surface have solidified. This process can be
conducted with the aid of a winding station and a downstream
consolidation station, as described, for example, in WO
2012/118379.
The thickness of the film has to be sufficient to be able to absorb
the winding forces. On the other hand, the film has to be
sufficiently flexible. The film generally has a thickness in the
range from 0.1 to 3 mm, preferably in the range from 0.3 to 2 mm
and more preferably in the range from 0.5 to 1.2 mm.
In step d2) or g), the tape is applied to the structure thus
obtained, or to the surface of the film which is rich in polymer B
[step d2)] or polymer C [step g)], with application of a contact
pressure. As in the case of the film, the necessary contact
pressure can be achieved through the winding tension or by means of
a contact body. Here too, in one embodiment, the two contact faces
are melted at the surface, for example by means of infrared
radiation, hot air, hot gas, laser radiation, microwave radiation,
or directly by contact heating. The partly molten contact surfaces
are then pressed against one another. The contact pressure should
then be maintained until the molten regions have solidified. In a
further embodiment, the tape is wound up and then melted from the
outside, either indirectly or else directly by means of a heatable
contact body. The heating output has to be calibrated such that the
outer surface of the previously applied film also starts to melt
here. Thereafter, the contact pressure is maintained until the
regions melted at the surface have solidified. The winding of the
tape and the winding-up of any further tape laminas in steps e) and
h) is prior art; no exact description of the procedure is therefore
necessary. For details, reference is made to the prior art cited in
the introductory part of the description.
If required in terms of application, subsequently to step h), one
or more further composite layers having a matrix composed of a
moulding compound based on another polymer can be applied if
cohesive bonding to the previous composite layer can be assured.
For example, adhesion can be generated in the same way as described
above by means of a single- or multilayer film of appropriate
construction. In the case of these further composite layers too,
the proportion by volume of the reinforcing fibres in the tape is
generally 10% to 85%, preferably 15% to 80%, more preferably 20% to
75% and especially preferably 25% to 70%, where the fibres are
preferably in the form of a unidirectional fibre lamina.
In order to protect the outer composite layer, it is optionally
possible, finally, to apply a layer that adjoins the composite
layer as outer cover lamina, composed of a reinforced or
unreinforced polymeric material. This is either a thermoplastic
moulding compound or a thermoplastic or crosslinkable or
crosslinked elastomer. The cover lamina preferably adheres firmly
to the outer tape lamina. For this purpose, it is advantageous to
choose the material for the cover lamina such that it comprises at
least 30% by weight of the same polymer as in the matrix for the
outer composite layer or of a polymer compatible therewith. In this
case, the cover lamina may be applied, for example, by means of a
crosshead extrusion die and hence be cohesively bonded to the outer
composite layer. If the cover lamina, however, is based on a
polymer which is incompatible with the material for the outer
composite layer, it is possible, in the same way as described
above, to generate adhesion by means of a single- or multilayer
film of corresponding makeup. Adhesion can also be generated by
crosslinking of a crosslinkable elastomer.
The invention also provides a thermoplastic composite pipe which
can be produced using the process according to the invention. It
comprises, from the inside outward, the following components: a) a
tubular liner having a wall comprising a thermoplastic polymer A in
the region of the outer surface; b) only if polymer A and polymer B
are different, an intermediate lamina which is directly and
cohesively bonded to the liner and in which the region of the
contact area bonded to the liner consists of a moulding compound
comprising polymer A to an extent of at least 30% by weight,
preferably to an extent of at least 40% by weight, more preferably
to an extent of at least 50% by weight, especially preferably to an
extent of at least 60% by weight and most preferably to an extent
of at least 70% by weight, and in which the region of the opposite
contact area bonded to the subsequent first composite layer
consists of a moulding compound comprising a thermoplastic polymer
B to an extent of at least 30% by weight, preferably to an extent
of at least 40% by weight, more preferably to an extent of at least
50% by weight, especially preferably to an extent of at least 60%
by weight and most preferably to an extent of at least 70% by
weight; c) a first composite layer which is directly and cohesively
bonded to the outer liner surface or to the intermediate lamina and
comprises reinforcing fibres in a matrix comprising polymer B, d)
an intermediate lamina which is directly and cohesively bonded to
the first composite layer and in which the region of the contact
area bonded to the first composite layer consists of a moulding
compound comprising polymer B to an extent of at least 30% by
weight, preferably to an extent of at least 40% by weight, more
preferably to an extent of at least 50% by weight, especially
preferably to an extent of at least 60% by weight and most
preferably to an extent of at least 70% by weight, and where the
region of the opposite contact area bonded to the second composite
layer consists of a moulding compound comprising a polymer C to an
extent of at least 30% by weight, preferably to an extent of at
least 40% by weight, more preferably to an extent of at least 50%
by weight, especially preferably to an extent of at least 60% by
weight and most preferably to an extent of at least 70% by weight;
e) a second composite layer which is directly and cohesively bonded
to this intermediate lamina and comprises reinforcing fibres in a
matrix comprising polymer C, f) optionally an outer cover lamina
composed of a polymeric material, where polymer A and polymer B are
the same or different and polymer B and polymer C are
different.
Preferably, the thermoplastic composite pipe consists of components
a) and c) to e) or a) and c) to f) (first embodiment) or of
components a) to e) or a) to f) (second embodiment).
The individual configurations of this thermoplastic composite pipe
will be apparent from the above details relating to the production
process.
In the process according to the invention, composite formation
between identical polymers in the critical process step achieves
better quality of adhesion. In addition, it is possible to use
single-layer liner pipes. Existing large pipe extrusion plants can
therefore continue to be utilized without modification. At the same
time, it is possible to choose less expensive polymers or polymers
that are more favourable for application purposes than the polymer
of the liner for the matrix of the composite lamina or of the
second composite layer.
The pipe according to the invention is especially suitable for
offshore applications in oil or gas production, for instance for
transport of the products to platforms, for connection to steel
pipes, as a transport pipe and especially, for example, as an
umbilical, as a riser, as a jumper line, as a flowline, as an
intervention line, as a downline, as an injection line or as a
pressure line. The invention likewise provides for the use for
transport of possibly pressurized hydrocarbons or mixtures thereof,
such as crude oil, crude gas, triphase (i.e. oil/gas/water
mixture), processed oil (already partly processed at the seabed),
processed gas, gasoline or diesel, of injection media such as water
(for instance to maintain the pressure in the cavern), oilfield
chemicals, methanol or CO.sub.2, and for conduction of hydraulic
oils (for example for actuators at the seabed). Furthermore, the
pipe according to the invention is also suitable as a
pressure-conducting line in the onshore sector or in other
industrial applications, especially in those where relatively high
forces have to be transmitted in the axial pipe direction with
force-fitting bonding between the pipe and connection element.
* * * * *